A conventional rotary die cutter comprises a magnet roller, an anvil roller arranged opposite to the magnet roller, a single flexible die mounted on the magnet roller and a sheet feed unit supplying a sheet one by one between the magnet and anvil rollers, in which the sheet supplied from the sheet feed unit is punched out by the flexible die (the term “punch” may be used to denote not only its original meanings but also “emboss”, “score”, “perforate” and so on. The same applies hereinafter.) while the sheet is conveyed by the magnet and anvil rollers (See, for example, JP 2003-237018 A and JP 2012-161859 A).
In such rotary die cutter, the punching of one sheet is completed each time the magnet and anvil rollers make one revolution because the punching is done with the conveyance of the sheet by the magnet and anvil rollers. Therefore, commonly, in order to maximize a production volume per revolution of the magnet and anvil rollers, that is, a. production volume per hour, the largest possible size of the flexible die (the flexible die extending over the whole circumference of the magnet roller) is used. This configuration is quite effective in mass production of the same type of product.
On the other hand, this conventional rotary die cutter has the disadvantages that a sheet needs to have a certain size adapted for the flexible die and the use of a small size of the flexible die causes reduction of a production volume per revolution of the magnet and anvil rollers. Consequently, even when a small amount of small-sized products which are considerably smaller than a processable size of sheet are produced, it is necessary to form a number of the same punching patterns on a large-sized flexible die and punch a certain size of sheet by use of the large-sized flexible die, which raises production costs.